The Pennsylvania Department of Health
today reported four confirmed and six probable human cases of influenza
due to a new strain of the flu known as H3N2v.

The Pennsylvania
cases occurred among youth participants in the Huntingdon County Fair,
Aug. 5-11. There are no reported hospitalizations. Although the
investigation is ongoing, there is no evidence to date of the new flu
strain spreading from person-to-person.This is the same virus that
has recently caused illness in Indiana and Ohio, mostly among children
who were exhibitors at or attended agricultural fairs. The illnesses
reported in Pennsylvania are also mostly in children and are typical
for the flu.

The above comments from the Pennsylvania
Department of Health report cite 10 likely H3N2v cases associated
with the Huntingdon County Fair
in central Pennsylvania. The 10 initial cases suggests the number
will rise, and this large number of cases once again signals human to
human transmission that is almost certainly not linked to swine.

The CDC released 10
more sets of sequences yesterday from cases in Ohio and
Indiana. All were a novel sub-clade first identified at a day
care center in West Virginia in late 2011, where there was no swine
exposure. The 23 ILI contacts signaled efficient transmission,
which has been seen at multiple
sites, including the above fair.

This novel H3N2v has rarely been noted in swine and it has clearly
adapted to humans. The most 20 recent H3N2v sequences, including
18 from 2012 have been the novel sub-clade from West Virginia.

The time for all fifty states to adopt this approach would be
useful. The upcoming school year will lead a major expansion of
cases, yet the true extent of the H3N2v spread is largely unknown due
to the current CDC approach which targets ILI cases with swine exposure.